This invention relates to a method of growing sod that requires substantially less time than conventional methods, e.g., less than fifty percent of the time required under conventional practice. The sod product obtained by the use of my process has several advantages, among which may be mentioned:
1. substantially weed-free product.
2. substantially less unit area weight, for easier handling and increased volume loading on flat bed trailers (weight is no longer the limiting factor).
3. ability to be shipped in much larger strips (or slabs), for quicker laying at the job site and more continuity in the finished sod installation.
4. a relatively strong dense root system.
5. greater sod production at a given facility, due to the shorter growing time.
6. a relatively clean sod product substantially free from loose soil.
7. a relatively strong sod product having intertwined roots that prevent the product from being inadvertently torn apart during shipment or subsequent handling at the point of end use.
An important feature of my invention is the use of compost (wheat straw, horse manure and combined water) as a growing medium; preferred medium is mushroom mulch, i.e., compost material already used for growing mushrooms. As far as I know, no one prior to my invention has used mushroom mulch as a sod-growing medium.
Another feature of my invention is the use of a porous net material at an intermediate level in the growing medium, i.e., between the lower surface and upper surface of the growing medium. The location of the net material advantageously gives the sod product maximum resistance against tearing, stretching, or breaking apart.
Prior to my invention others have proposed sod-growing methods that are in some respects related to my proposed method.
U.S. Pat. No. 4,720,935 to Rogers discloses a sod-growing medium comprised of about 70 percent water-absorptive wood fibers and about 30 percent non-water absorptive cellulose particles. The wood fibers can be papermill by-products; presumable the wood fibers would be sawdust. The cellulose particles can be rice hulls or chopped straw having maximum lengths less than about one-half inch.
U.S. Pat. No. 4,716,679 to Heard discloses a sod-growing medium comprised of comminuted (chopped) straw having lengths in a range between about one-fourth inch and three-fourth inch. The straw is deposited on an inert sub-surface to a depth ranging between three-fourth inch and 11/4 inch. Grass seed is applied to the upper surface of the straw layer in slurry form. Alternately, the grass seed may be pre-mixed with a second quantity of chopped straw and then deposited onto the base straw layer in dry or slurry form. The upper layer (seed and chopped straw) has a preferred thickness ranging up to about one-half inch. Judging from the patent drawings, the straw length in the upper layer is less than one-half the straw length in the base layer.
U.S. Pat. No. 3,863,388 to Loads discloses a sod-growing medium that can be either a mixture of soil and peat, or an exfoliated mineral preparation, or a decomposable cellular resin foam material. The sod-growing medium is deposited onto an inert mesh material having square mesh openings measuring about one-fourth inch on a side. The sod-growing medium is laid to a depth of about three-eighth inch. The patentee indicates that the grass roots grow downwardly through the openings in the mesh material, and then laterally underneath the mesh material; the roots bond to the inert mesh material. The patentee does not indicate any particular thickness for the layer of sod-growing material. However, judging from the size of the mesh openings (FIG. 6), the growing medium would have a layer thickness of about one-half inch.
My proposed method differs from the methods disclosed in the above-mentioned patents.